Assembly-to-clamp visual indicator unit with press-to-test pushbutton cap



Aug. 4, i970 l J. w. AMIS. JR.. ETAL 3,522,500

ASSEMBLETO-CLAMP VISUAL INDCATOR UNIT WTH PRESSTOTEST PUSHBUTTON CAP Filed April 19. 1967 MAUR/f6 D. /fz/Zze' By @er s. ANDERSON United States Patent O m 3,522,600 ASSEMBLY-TO-CLAMP VISUAL INDICATOR UNIT WITH PRESS-TO-TEST PUSHBUTTON CAP James W. Amis, Jr., Bellevue, and Maurice D. Fuller and Gary E. Anderson, Seattle, Wash., assignors to Korry Manufacturing Co., Seattle, Wash., a corporation of Washington Filed Apr. 19, 1967, Ser. No. 631,986 Int. Cl. G08b 5/ 00 U-S. Cl. 340-381 9 Claims ABSTRACT F THE DISCLOSURE A panel-mounted press-to-test pushbutton electrical indicator assembly is disclosed in which a flanged socket housing for the assembly is secured on the panel by ernploying the contact base for the pushbutton cap as a takeup and retainer means for cooperating with the flange in clamping the housing to the edge of the panel opening. Double acting electrical contact means yieldably interposed between the cap and the base make it possible to pass current into and out of the indicator device, yet individually displace each of the `base and the cap toward the position of the other during the respective steps of mounting the housing and testing the cap.

FIELD OF THE INVENTION This invention relates to electrical indicator units, and more particularly to indicator units of the plug and socket type which are mounted on a support panel, in mass numbers of the same unit, to carry indicator devices which indicate a variety of incoming intelligence from external circuitry; and which do so reliably through the use of plug in press-to-test push button caps for mounting the device in the units.

One object of the invention is to devise an electrical indicator unit of this type which is more economically co-nstructed, and simpler to employ, by virtue of using a twopart socket device for each cap, which comprises a flanged open-ended socket housing, and an electrical contact base for the socket of the housing, which is detachably secured to the rear of the same, so as to cooperate with the flange of the housing in clamping the unit to a support panel.

Another object of the invention is to device an indicator unit of this nature in which the socket device is selfclamping to the support panel at the time it is assembled.

A still further object is to devise such a self-clamping unit which is capable of being wired-in before it is assembled, as by mounting a printed circuit board on the contact `base, and Wiring the board to the external circuitry for the indicator device, before the base is secured to the housing. g

Another object is to devise a unit of this nature wherein the base can be held in one hand behind the panel, and secured to the housing, by the application of force to the unit with the other hand, from the front of the panel.

Still further objects include devising a unit of the foregoing nature which does not prohibit using a press-to-test motion for the test operation, and which still makes it possible to use a plug in, press-to-test pushbutton cap that is removable for purposes of replacing lamps or other indicator devices in the cap.

The invention also has the object of devising a system whereby indicator caps of this nature can be distinguished from one another as to their suitability for the signal wired into the socket device.

y 0 Still further objects will be apparent from the descrip- 7 tion of the invention which follows hereafter.

3,522,600 Patented Aug. 4, 1970 SUMMARY OF THE INVENTION These objects and advantages are realized by an electrieal indicator unit of our invention which comprises an elongated, open-ended outwardly ilanged socket housing, and an electrically insulative contact base for the socket of the housing, which is detachably secured to the rear of the housing, and laterally outstanding therefrom so as to cooperate with the ange of the housing in clamping the unit to the surrounding edge of an opening in the support panel. It also comprises a plug in, press-to-test pushbutton cap which is removably inserted and detained in the front of the socket, Vand displaceable in either longitudinal direction thereof. The cap is adapted to carry on electrically operated indicator device, and there is a plurality of electrical contacts on the opposing faces of the cap and the base, wherebyunder normal operating conditions current is passed into and out of the indicator device; and an additional test contact on the base, at a relatively rearwardly recessed location spaced from the aforesaid face thereof, whereby under test conditions a test circuit is closed to determine the operability of the indicator device. Electrical contact means in the socket of the housing, intermediate the base and the cap, electrically interconnect the contacts 0n the faces thereof, under each of the aforesaid sets of conditions. These contact means comprise a normally closed electrically insulated contact member having double acting resilient biasing means caged between the base and the cap, and a pair of oppositely directed, slidably guided contact plungers which are interposed between the biasing means and each of the base and the cap, and urged by the biasing means into contact with electrical contacts on the faces of the same. They also comprise an electrically insulated actuator rod in the test circuit, which is slidably guided between the test contact and the cap, and biased in. the direction of the cap, to assume a normally open position spaced from the test contact, but displaceable against the latter bias to contact the test contact when the cap is displaced in the longitudinal direction of the housing relatively toward the base.

Preferably, the base has a printed] circuit board on the face thereof, over the recess, and the aforesaid actuator rod is slidably guided in the board, and biased to assume a normally open position spaced from the bottom of the recess, whereon the test contact is mounted. In addition, a spacer sleeve is telescopically engaged about the housing, to abut with the`base in clamping the unit to the edge of the opening in the panel. The electrical contact means are mounted on a carrier block interposed in the socket of the housing between the base and the cap. The carrier block has a longitudinally extending bore therethrough receiving the actuator rod, and an actuating plunger on the cap is operable within the bore, to displace the rod against its bias when the cap is displaced in the direction of the base. Also, the block has fastener means thereon, which are detachably secured to the base, to in turn secure the` latter to the housing, and the fastener means are exposed to the cap so that when the cap is removed from the socket, they may be detached from the base, to thereby detach the base from the housing, by applying force to the fastener means in the longitudinally front-ward direction of the socket.

The preferred embodiments of the invention also employ detent means for removably detaining the cap in the socket, which comprise diametrically opposed latch arms in the socket of the housing, having spring biased detents adjacent the relatively front ends thereof, and correspondingly diametrically opposed lugs on the cap, which are slidably engageable in the arms by` overcoming the bias of the detents, for displacement in either longitudinal direction of the socket.

In addition, as another feature of the invention, each socket and plug device formed 'by the foregoing members, has cooperably engageable indexing means thereon which are uniquely coded with respect to each other socket and plug device, so that the plug-in cap of one device is insertable in only one socket among the plurality of sockets provided -by the socket devices in the overall panel assembly. Preferably, the indexing means are formed on the mutually opposing inside and outside faces, respectively, of the socket and plug device, and are engageable by insertion of the cap into the socket through the front end opening thereof. For example, as illustrated hereinafter, they may comprise slidably engageable keying elements on the mutually opposing faces of the socket and the cap.

BRIEF DESCRIPTION OF THE DRAWING These and other features of the invention will be better understood by referring to the accompanying drawing wherein we have ill-ustrated one of the preferred embodiments of the invention.

In the drawing:

FIG. l is an exploded isometric view of the principal components of an indicator unit constructed in accord with the invention;

FIG. 2 is a rear perspective view of one of the components;

FIG. 3 is a horizontal longitudinal part cross-sectional view of the indicator unit in FIG. l, when assembled and mounted for use on a support panel, the section having been taken in two planes to detail the construction of certain components; and

FIG. 4 is a 'vertical longitudinal part cross-sectional view of the unit,

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing a single indicator unit is illustrated. However, as mentioned earlier, units of this type are commonly employed in mass numbers as part of a larger indicator panel assembly. The drawing is not indicative of the full assembly, therefore, and the reader will appreciate that in practice the panel would appear as a far larger plate-like member 2 having a multitude of openings 4-in this case rectangulareach of which contains one of the indicator units.

The individual units themselves have live principal components, including an elongated tubular metal sheath 6 which is complemental in cross section to each opening 4, so as to be slidably insertable in the opening as a housing for the remaining components of the unit. One of these is a plug in, press-to-test pushbutton indicator cap 8 which is removably inserted and detained in the socket 10 of the housing, to communicate meaningful intelligence to an operator or observer of the assembly. Intelligence is presented to the observer when an indicator signal from external circuitry, electrically energizes a pair of lamps '12 supported in the cap. The lamps optically form or project indicia 13 of the intelligence on the outer face of the cap. The signal is transmitted to the cap through an electrically insulative support 14 which forms a contact base for the socket of the housing. The base also operates to clamp the unit to the panel, in cooperation with an outturned flange 15 on the front end of the housing, and a fourth component comprising a metal spacer sleeve 16 telescoped about the housing. The contacts on the base and the lamps are electrically interconnected by the fifth component, which comprises a drilled, electrically insulative carrier 'block 20` having a plurality of doubleacting spring biased contact members 18 mounted therein. The block 20 is secured in the socket of the housing as a cross member between the base and the cap, and has the base detachably secured thereto. A test actuator rod 22 on the base, is received in one bore 24 of the block.

The cap 8 comprises an integrally formed lamp base 26 and lamp cover or shell 28 of plastic, ceramic or other insulative material, forming an enclosure about the lamps. The lamp base is sized to fit within the socket 10 of the housing, and has a pair of apertures in which anged contact bushings 30 are inserted, and then riveted or otherwise fastened to the base, to form sockets for the lamps. The lamps have flanged contact buttons 32, and are inserted in the bushings from the rear of the cap, as seen in FIG. y2, so that the contact buttons are exposed to the interior of the socket 10. Thumbnail notches 33 in the edges of the bushings enable the lamps to be removed when necessary or desired. Also, a contact plate 34 acts as a common ground for the lamps.

When inserted, the bulbs 35 of the lamps project forwardly into the cap enclosure so that the light from the same is projected through a rectangular rim or frame 36 which surrounds the forward end of the enclosure. The frame supports a pair of translucent plastic plates 38 and 40 which are glued or otherwise secured in tandem in the frame. The outer plate 38 carries the indicia y13 of intelligence while the inner plate 40 is colored to diffuse the light emanating from the bulbs.

An electrically insulated rod-like actuator plunger 42 is secured to the lamp base so as to extend in the longitudinally rearward direction of the housing when the cap is inserted in the socket thereof.

The cap is removably detained in the socket by means of cooperatively engaging detent means formed on the sides of the respective elements. The sidewalls of the socket have a pair of resilient latch arms 46 soldered or otherwise secured thereon, each of which comprises a pair of thin, at, elongated, resilient metal strips 48 which are interconnected and secured to the housing at their relatively rear ends. The strips extend in spaced parallel relationship along the length of the socket, and are equipped with rounded teeth 50 at their relatively forward ends. The teeth are directed at one another, but spaced apart by a slight clearance. To interengage with the arms, the cap carries a pair of laterally projecting lug rivets 52 which are recessed in longitudinally extending slots 54 in the sidewalls of the lamp base. As the lamp base is inserted in the socket, the lugs of the rivets enter the clearances between the teeth of the strips, and spread the strips apart. The walls of the slots limit the separation of the strips, however, and as the rivets pass beyond the teeth, the strips snap back into parallel condition, leaving the rivets slidably engaged between them. Thereafter, if the cap is inserted still further, the strips act as tracks or rails which guide the motion of the cap into the socket. Normally, when the cap is released, it is biased into the relatively forwardly seated position of FIG. 3, immediately behind the teeth, as shall be explained hereinafter.

The carrier block 20 has a basic rectangular form which is adapted to insert within the socket of the housing, where it is secured by cooperatively engaging lock features on the respective members. Each of the lower left-hand and upper right-hand corners 6c at the rear end of the housing is partially omitted or removed, to terminate these portions of the sidewalls of the housing at a transverse plane disposed somewhat forwardly of the end. In addition, a pair of transversely oriented and transversely offset slots 58 are formed in the upper and lower faces of the housing, to leave a narrow transverse strip 60 of metal across the end of each face, adjacent each of the aforementioned corners 6c. The strips enable the carrier block to be seized within the housing when the unit is assembled.

Each of the upper left-hand and lower right-hand 1ongitudinal shoulders 20s of the block is omitted or removed, with the exception of a small fillet 209 at the inside of each shoulder; and each of the front corners 20c of the remaining shoulders is also omitted or removed, so that only the back corners 20b remain at the sides of the block. In addition, portions of the upper and lower faces of the block are similarly omitted or removed, to form a pair of transversely-spaced plateaus 20p and a transversely extending rib 201 on each face. The ribs are sized and transversely positioned to it within the slots `58 in the upper and lower faces of the housing; and are spaced from the plateaus by transversely extending grooves 64 which correspond in width to the narrow strips on the housing. The grooves are substantially coplanar with the relatively front faces of the back corners 2Gb of the block.

When the -unit is assembled, the block is inserted into the rear end of the housing until the strips 60 register with the grooves 64; and then the strips are depressed into the grooves, by applying a pair of narrow-nosed pliers to each strip through the spacing between the plateaus. The act of depressing the strips into the grooves locks the ribs 20r within the opposing slots 58 of the housing, and at the same time takes up enough material in the upper and lower faces of the housing to deflect the sidewalls of the same into locking positions behind the |back corners 20h of the block.

The block may be secured in the housing, either before or after the housing is inserted in the opening of the panel.

The block has a total of six longitudinally drilled or formed passages 66', including the passage 24. The two sidemost passages are adapted to accommodate a pair of threaded clamping bolts 68 which are inserted in the passages from the front of the block. When the unit is assembled, the threaded ends of the bolts are received in the base 14, to detachably secure the base to the housing, as shall be explained hereinafter. Of the two centermost passages, the upper 24 is adapted to receive the actuator rod mentioned previously, and in addition receives the actuator plunger 42 on the cap when the cap is inserted in the housing. The three remaining passages, including the lower center passage, serve as mounting bores 66' for the electrical Contact members 18 which electrically interconnect the base with the contact buttons 32 of the lamps.

Each of the Contact mem'bers 18 comprises an elongated hollow cylindrical metal shell 68 which is apertured at its ends and inserted lengthwise within its respective bore. In order to secure the shells in the mounting bores, each bore 66 has an annular rib 70` adjacent the rear end thereof, and a slight lengthwise projection on the rear end of the shell 68 is inserted through the rib, and then peened or riveted about it from the rear. Caged within the shell, is a coiled spring 72 and a pair of oppositely directed, flanged contact plungers 74. The IShanks of the plungers are slidably guided in the apertured end walls of the shell, while the spring is interposed between the flanges 76 of the plungers to bias them in the opposite longitudinal directions of the socket. The plungers biased into the forward end of the housing make contact with the ground plate 34 and the contact buttons 32 on the lamps, when the cap is inserted in the socket. In addition, the combined bias of the coiled springs, urges the cap into its forwardmost detented position on the arms 46, where it remains under normal operating conditions, as seen in FIG. 3. The rearwardly directed plungers make contact with corresponding contact elements on the base, as shall be explained hereinafter.

The base 14 is also of basic rectangular block form, and is constructed of insulative material which is usually similar to that used in the carrier block. The front face of the base is deeply relieved so as to form a recessed seat 78 for a printed circuit board 80 which is secured to the base. Printed circuit boards are widely known and essentially comprise a card of plastic or other insulative material, on which thin conductive metal strips and pads are printed, in the sense of being substantially flush with the surface of the card, to form a series or pattern of electrical contact elements 82 which may be connected in circuitry leading into and out of the board. In fabricating the base, corbels `84 are formed at diametrically opposed corners of the recess 78 toact as seats for the board. The board is thus elevated above the bottom of the recess and a shallow chamber 86 is formed between the two. In addition, four small receiving wells 88 are formed in the back of the base, one of which 8S is coaxial with the bore 24 in the carrier block and the actuator plunger 42 on the cap. The bracket arms 89 of four L-shaped terminal posts 90 are secured in the wells by electrical contact bushings or eyelets 92, riveted in apertures interconnecting each well with the chamber 86. The posts 90` are electrically interconnected with the contact elements 82 on the board, by electrical leads 94 soldered to the elements and passed. into the eyelets. An exception is made in the case of the aforementioned one well 88', however. In this case, a solid contact rivet 96 is secured in the corresponding aperture to form a test contact on the bottom of the recess. In addition, at an opposite position on the board, a small opening 98 is made to receive the actuator rod 22. The rod is slidably engaged in the opening, and is biased into its position within the bloc-k, by a coil spring 1'00 interposed between the board and a ferrule 102 on the outlying end of the rod. A flange 10-4 on the other end of the rod limits its motion in the longitudinally forward direction.

The eye 106 of each post 90 has an appropriate electrical lead 108` from the external circuitry, and when the base is secured to the housing, the rearwardly directed plungers 74 of the contact members engage appropriate contact elements y82 on the board to close the circuits to the lamps 12, each of which is also interconnected in the test circuit with the actuating rod 22 on the board. However, under normal operating conditions, the flange 104 of the rod is spaced from the test contact 96 and, therefore, the test circuit is normally open as seen in FIG. 3.

Diodes 110' on bent upright electrical leads 112, interconnect the contact elements 82 on the printed circuit board, as part of the circuitry formed thereon. The resistance elements are positioned at diametrically opposed locations on the board which correspond to the relieved shoulders 20s of the block, so that when the unit is assembled, the element insert conveniently within longitudinal passages formed at these shoulders by the unremoved corners 6u at the rear of the housing. Also, the corbels 84 are disposed at locations corresponding to the unrelieved shoulders 20u of the block, and have passages 114 drilled therethrough which are counterbored v'at the back of the base and lined with thin bushing 116 adapted to pass the clamping bolts 68 on the block 20. The bushings have threaded flange nuts 116 on their heads which seat in the counterbores of the passages,` and interengage with the threading on the bolts to secure the base to the housing. The bushings are riveted into position so as to remain with the base at all times, the arrangement being such that they alsov serve to secure the circuit board 80 to the base.

As seen in the drawing, the recess 78 of the base conforms in dimension to the outside dimensions of the housing, so that the base can slide overl the rear end of the housing after the block 20 is secured therein. Also, the outside dimensions of the base conform to those of the spacer sleeve 16, so that when abutted, the combined members form a smooth outside surface for the unit. In-

terlocking notches 1:18 and tabs 120 on the sleeve and i base, respectively, assure that the members are iixed in relation 'to one another.

In assembling and mounting the unit on the support panel 2, the first step is to insert the housing 6 through the opening 4 in the panel until the outturued liange 15 of the housing abuts the face of the panel. Generally, the drilled carrier block 20 is inserted and secured within the housing before the latter is pushed through the opening of the panel. However, this need not be the case, as mentioned earlier. In all events, the next step is to slide the spacer sleeve 16 over the housing and to run it upV against the rear face of the panel. This interposes the peripheral edge of the opening between the sleeve and the flange 15, so that when the base 14 is subsequently applied to the housing, and the clamping bolts 68 are interthreaded with the nuts 116' in the corbel holes 114, the reaction of the threads has the effect of clamping the sleeve between the base and the back of the panel. Thus, in the single step of screwing the bolts into the nuts, the operator simultaneously integrates the unit, and clamps it to the panel. Ordinarily, he can accomplish this by reaching behind the panel with one arm to support the base, while he takes up the weight of the base with the bolts, by applying a screwdriver to each bolt from in front of the panel.

If he chooses to do so, the operator can wire in the base with the external circuitry, before he assembles the unit. While holding the base in his hand, for example, he can select the appropriate wires and solder or otherwise secure them to the eyes 106 of the terminal posts, before he applies the base to the rear of the housing. Likewise, should one of the resistance elements 110, or some other element in the system, fail, the base can be readily removed and replaced with another such element, by loosening the bolts 68 and slipping it off of the back of the housing.

The final step is to insert the indicator cap 8. To assure that the appropriate cap is inserted in the housing, a system of coded indexing means is used on the panel assembly. One such set of indexing means is seen on the illustrated unit. The upper wall of the housing has a pair of transversely spaced tabs 122 depressed therefrom into the socket. Also, another such tab 122 is raised into the socket from the lower wall of the housing, at a location intermediate the upper tabs. At transversely corresponding locations in the upper and lower faces of the lamp base, there are endwise slots 124 in the body of the base. When the cap is inserted in the socket of the housing, the slots 124 slidably engage with the tabs 122; however, this is only possible because the slots and tabs are complementally sized and oriented, or coded to one another on this particular unit. In the case of another indicator cap, they might not be so sized and oriented, and the cap would not be allowed to seat within the socket. Therefore, this arrangement provides a means of distinguishing one cap from another, in terms of the suitability of the intelligence thereon, to the indicator signal wired into the base. Hence the operator need not fear, for example, that a cap marked missile out of orbit is in fact only an indicator of excessive temperature or something of the sort, due to an error in the selection of the caps for the units.

The depth of the slots 124 from the back of the lamp base, is such that the tabs may slide within the slots when the unit is tested for the operability of the lamps.

What is claimed is:

1. In combination, an elongated open-ended socket housing for mounting in an opening in a panel, and having a laterally outwardly extending flange on the open-end portion thereof to be abutted against the panel on one side thereof adjacent to the edge of the opening, a sleeve-like abutment member slidably engaged over the housing for abutment against the other side of the panel, an electrically insulative contact base slidably engaged on the other end portion of the housing and connected with the abutment member to apply the same against the edge of the opening on the aforesaid other side of the panel, during the mounting of the housing, the housing having a cross member fixed therein, and retainer means interconnected between the cross member and the base to cause relative sliding movement between the base and the housing whereby the edge of the opening is clamped between the flange and the abutment member to secure the housing on the panel; and a press-to-test pushbutton cap slidably detained in the open end portion of the housing, to carry an electrically operated indicator device thereon, there being electrical contacts on the opposing faces of the cap and the base, and double acting electrical contact interposed between the cap and the base on the cross member, which are yieldably engaged with each of the cap and the base to electrically interconnect the contacts on the faces thereof, whereby current is passed into and out of the indicator device from the base, yet each of the base and the cap is individually displaceable relatively toward the position of the other, during the mounting of the housing and the testing of the cap, respectively.

2. The combination according to claim 1 wherein the face of the base is recessed to slidably engage over the aforesaid other end portion of the housing, and the contacts on the face of the base are disposed within the recessed portion thereof.

3. The combination according to claim 2 wherein the latter contacts on the' face of the base are formed by a printed circuit board seated in the recess thereof.

4. The combination according to claim 3 further comprising an additional test contact on the face of the base, at a location relatively rearwardly spaced from the first mentioned contacts thereon, and an electrically insulated switch contact which is slidably mounted between the test contact and the cap, and yieldably biased in the direction of the cap to assume a normally open position spaced from the test Contact, but displaceable against the latter bias thereon to engage the test contact when the cap is displaced relatively toward the base.

5. The combination according to claim 4 wherein the printed circuit board is seated above the bottom of the recess, and the test contact is disposed therebelow, on the bottom of the recess, there being an aperture in each of the printed circuit board and the cross member, in which the switch contact is slidably guided between the test contact and the cap.

6. The combination according to claim 4 wherein the cap has a rearwardly extending electrically insulated actuator rod thereon which is operative to displace the switch contact against the bias thereof.

7. The combination according to claim 1 wherein the electrical contact means includes resilient biasing means caged within the cross member, and a pair of oppositely directed slidably guided contact plungers which are interposed between the biasing means and each of the base and the cap, and urged by the biasing means into contact with the electrical contacts on the faces of the same.

8. The combination according to claim 1 wherein the retainer means includes rotatable fastener means which are mounted on the cross member and threadedly engaged with the base, for relative displacement thereof during the mounting of the housing.

9. The combination according to claim 1 wherein the other end portion of the housing is also open-ended, and the cross member is formed by an apertured carrier block which is fixedly interengaged with the housing in the end opening of the aforesaid other end portion thereof.

References Cited UNITED STATES PATENTS 2,710,954 6/1955 r,[-Iallerberg et al. 340-381 X 2,938,200 5/1960 Dupree 340-381 3,019,428 1/l962 Arrasmith 340-381 3,040,142 6/1962 Dietrich 340-381 X 3,099,771 7/1963 Matiyak 340-381 X HAROLD I. PITTS, Primary Examiner Us. C1. X.R. 

